Glue the sun to HDRI

[smicha]

Is there a way to glue/fix the sun to a certain position on a HDRI map so that when I use X and Y transforms to move the sky map - the sun also would move? On my simple scene I moved the sun to the spot where the real sun is located. Every time I move the sky I must precisely move the fake sun. This is so time consuming.

If this is not possible (or extremely hard to code) another nice update would be to be able to drag the sun (its position) directly on the sky.

[Seekerfinder]

Ooo. Good idea Smicha!!

Onto the wishlist!

Seeker

[Rikk The Gaijin]

Why do you need to add the sun with an HDRI?

[Draydin_r]

Hdris tend to lack the hard shadows that a dynamic light source provides (ie. Sun, lamps, headlights, candles etc.). The recent addition of the Sun-HDR blend addresses this by providing a Sun to match with the environment (with sufficient tweeking).

I think this is a fantastic addition as it makes the already robust SunSky system of 1.5 even more controllable! The the only (note the only ) grip I might have is exactly what Rikk brings up. I would like to point toward the HDR Labs product (http://www.hdrlabs.com/sibl/)SIBL. This system is a plugin for most of the major renders (though Lightwave is more up to date) that creates scenes that combine the qualities of hard lighting and HDRI environments. They even give the artist control of where to place the sun in the scene, save them as presets, and link them together so when you move one you move the other.

If Octane could adopt even a couple of these features it would make the system near perfect! Imagine HDRSun Presets on LiveDB

But that is my two cents (barring exchange rate ), take this for what you will.

[roeland]

Maybe the norhtoffset parameter should also rotate the texture environment. We can have a look at this later.

The sIBL files are plain text files which can be read with a script, I have created a script which loads a file and sets up what is currently supported in Octane (a lat-lon-mapped environment + a sun direction). Get the script here.

--
Roeland

[riggles]

I think of sIBL as a sort of temporary solution or workaround that isn't really needed any more. With modern GPUs and Importance Sampling especially, we can get very sharp shadows and accurate lighting from quality HDRIs and don't need the blurred GI HDRI/sharp reflection map/linked direct sunlight method of old with sIBL.

[Rikk The Gaijin]

If you don't get a sharp shadow from your HDR, it means that HDR was not properly created. Even in that case, you can always fix it in Photoshop, by paint an intense value over the sun.
In my experience, I found the Aversis HDR maps among the best HDR on the market.
http://www.aversis.be/hdri/hdri-collections.htm

[smicha]

Rikk,

Thank you for valuable info. I just played with the sun and HDRI and noticed that placing the sun on the brightest spot on HDRI gives extra control on shadows via the sun size, turbidity and power. And it's quick and easy.

[ROUBAL]

You can make very efficient HDR images within Octane :

Using a panoramic camera and the sunlight system, capture your scene (without the central element : for example without the car if you want to render a car) with the camera placed at the center of your scene.

Save as exr file, and reuse this file as a HDR environment.

Obviously, the image is more interesting if you have some physical models in your scene (landscape, buildings...)

you can edit the HDR afterward in an image editor supporting HDR formats.

[hdrmaps]

If you have un-clamped hdri you don't need paint on hdri or use extra direct light placed at sun.
I recorded short video about how to paint on clamped hdri - https://www.youtube.com/watch?v=_olHJZ3BV_A

If you want you can use reflection hdri from this sIBL pack http://goo.gl/iT1JtD
Test it - it produces really nice, sharp shadows (my setup is Power 4.0, IBL Gamma 1.15, Importance Sampling ON)